The present invention relates to a method for preventing and improving diabetes and liver dysfunction.
In recent years, in Japan, reflecting the progressive increasing in elderly population and the westernization of diet, the incidence of various deseases of adult people has increased. Among them, diabetes is a generic term of chronic high blood glucose and various complications (such as retinopathy, neuropathy, nephropathy and immune disorder) induced by capillary dysfunction accompanying the chronic high blood glucose, and it is estimated that domestically about five million patients are suffering from them. Diabetes is generally classified into insulin dependent diabetes mellitus (IDDM) and non insulin dependent diabetes mellitus (NIDDM). In Japan, it is reported that IDDM patients account for at most 5%, while NIDDM patients account for at least 95%. Particularly, NIDDM which is related to habitat factors such as obesity, overfeeding, ataxia and senescence, is expected to increase in the future in Japan where the progressive increasing in elderly population and the westernization of diet, will further advance.
As the causes of IDDM, it is generally known that viral infection or defects of autoimmunization mechanism causes inflammation of Langerhaus islet of pancreas, resulting in the destruction of beta-cells as the insulin-producing cells, whereby insulin will not be secreted to develop IDDM. Accordingly, treatment is made by administration of insulin.
Further, as the causes of NIDDM, it is believed that although insulin is secreted, the action of insulin on cells is inadequate, whereby the cells can not take glucose in the blood sufficiently and a hyperglycemia state is thereby continued. Accordingly, for the treatment, insulin is not necessarily required and dietary treatment and excercise treatment are mainly used.
If the hyperglycemia state is continued by diabetes, systemic capillary will fall into disorder and arteriosclerosis will advance, thereby causing obstruction of blood vessels in heart or brain and gangrene of legs. Further, if the blood glucose level is high, glucose in the blood is likely to bond to proteins in hemoglobin or tissues, whereby the functions thereof will be inhibited. As the results, complications such as retinopathy, nephropathy, neurosis, cerebral infarction, myocardinal infarction and cataract, are occurred. Further, since immunization power is decreased by diabetes, the patients are likely to catch infections easily.
If the complications become worse, recovery is very hard, and it is thereby important for the patients of diabetes to control the blood glucose level so that it will not rise above such level that no symptom is observed. For such a purpose, various antidiabetic agents such as hypoglycemic agents have heretofore been developed. For example, there may be mentioned, as natural materials, a hypoglycemic agent containing as an active ingredient, tea lactone as a water-soluble polysaccharide component of tea leaves (Japanese Unexamined Patent Publication No. 4-124139), an antidiabetic agent containing as an active ingredient, a hot water extracted fraction of banaba leaves (Japanese Unexamined Patent Publication No. 7-228539), a hypoglycemic agent of a xanthone extracted and isolated from Japanese green gentian (Japanese Unexamined Patent Publication No. 7-206673), and the like; and as chemically synthesized products, a moranolin N-substituted derivative (Japanese Examined Patent Publication No. 59-43949), a thiazolidine compound (Japanese Unexamined Patent Publication No. 4-210977) and a condensed 7-membered cyclic compound having an imidazolyl group (Japanese Unexamined Patent Publication No. 4-178381), and the like.
The chemically synthesized products generally exhibit potent effects, but give unwanted side effects, whereby a long term administration accompanies many problems. While the natural extracted products are high in the safety, but mostly exhibit no adequate effects.
On the other hand, with respect to liver dysfunction as other one of the deseases of adult people, the degree can be grasped by indices such as COT or GPT in biochemical inspections of, for example, periodical medical checkup, and it has become easy to find disorders.
Liver plays important rolls in vivo, for example, detoxication, metabolism or storage of sugar, protein or lipid, and hormone control. Dysfunction of liver often leads to fatal results for living bodies. It is well known that the causes of liver dysfunction represented by hepatitis, are based on the habit of life, for example, over ingestion of alcoholic beverages, heavy drinking, heavy eating, irregular life or stress. However, it has been found that the liver dysfunction is often caused by hepatitis virus. Especially, if viral hepatitis becomes chronic, it will often become hepatic carcinoma through liver cirrhosis, whereby suitable preventing and improving method has been demanded.
Many proposals have heretofore been made as a preventing and improving agent for hepatitis. However, chemically synthesized products generally exhibit potent effects, but have side effects, thereby being problematic for a long term administration, while natural extracted products are mostly high in the safety, but exhibit no adequate effects.